diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 437052b..9fa3e1a 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -17,7 +17,7 @@ jobs:
               #- macos-latest
               #- windows-latest
         ocaml-compiler:
-            - '4.05.x'
+            - '4.08.x'
             - '4.14.x'
             - '5.0.x'
 
diff --git a/dune-project b/dune-project
index 5e0c97a..209124a 100644
--- a/dune-project
+++ b/dune-project
@@ -15,7 +15,7 @@
  (name trace)
  (synopsis "A stub for tracing/observability")
  (depends
-   (ocaml (>= 4.05))
+   (ocaml (>= 4.08))
    dune)
  (tags
   (trace tracing observability profiling)))
@@ -24,7 +24,7 @@
  (name trace-tef)
  (synopsis "A simple backend for trace")
  (depends
-   (ocaml (>= 4.05))
+   (ocaml (>= 4.08))
    (trace (= :version))
    (mtime (>= 2.0))
    base-unix
diff --git a/trace-tef.opam b/trace-tef.opam
index 026ee06..1c21349 100644
--- a/trace-tef.opam
+++ b/trace-tef.opam
@@ -8,9 +8,9 @@ tags: ["trace" "tracing" "catapult"]
 homepage: "https://github.com/c-cube/trace"
 bug-reports: "https://github.com/c-cube/trace/issues"
 depends: [
-  "ocaml" {>= "4.05"}
+  "ocaml" {>= "4.08"}
   "trace" {= version}
-  "mtime"
+  "mtime" {>= "2.0"}
   "base-unix"
   "dune" {>= "2.9"}
   "odoc" {with-doc}
diff --git a/trace.opam b/trace.opam
index ea1e948..e1e7b9a 100644
--- a/trace.opam
+++ b/trace.opam
@@ -8,7 +8,7 @@ tags: ["trace" "tracing" "observability" "profiling"]
 homepage: "https://github.com/c-cube/trace"
 bug-reports: "https://github.com/c-cube/trace/issues"
 depends: [
-  "ocaml" {>= "4.05"}
+  "ocaml" {>= "4.08"}
   "dune" {>= "2.9"}
   "odoc" {with-doc}
 ]